I had this issue and none of the suggestions I found worked. In the end it turned out to be the operating system on one of the machines. I had one running Vista and one Win7. No matter what I did I had a tunnel problem. Upgraded the Vista machine to Win7 and it works perfectly.
The thread was already revived, so I'll give my take on it.
If you check in Network and Internet > change adapter settings and you check for the actual driver for hamachi, It doesn't show up for my windows 8. I just have my wifi, lan, and tunngle. Anyone have any ideas?